title: Confocal microscopy for the histological fluorescence pattern of a recurrent atypical meningioma: case report.
abstract: BACKGROUND
  Fluorescence-guided resection with 5-aminolevulinic acid (5-ALA), which has shown promising results in the resection of malignant gliomas, has been used for meningioma resection in an attempt to more clearly delineate the tumor margin. However, no article has investigated the fluorescence pattern of meningiomas on a histological level. Understanding the microscopic pattern of fluorescence could help assess the precision and utility of using 5-ALA for these tumors. We present the case of a recurrent atypical meningioma operated on with 5-ALA fluorescence-guided resection for delineation of tumor tissue from surrounding uninvolved dura.
  
  
  METHODS
  A 53-year-old woman presented with recurrent atypical meningioma of the falx. Prior treatment included surgical resection 6 years earlier with subsequent fractionated radiation therapy and radiosurgery for tumor progression. The patient was given 5-ALA 20 mg/kg body weight dissolved in 100 mL water 3 hours before induction of anesthesia. Intraoperative fluorescence was coregistered with preoperative imaging. Neuropathological analysis of the resected falx with confocal microscopy enabled correlation of fluorescence with the extent of tumor on a histological level.
  
  
  CONCLUSIONS
  Fluorescence guidance allowed clear intraoperative delineation of tumor tissue from adjacent, uninvolved dura. On a microscopic level, there was a very close correlation of fluorescence with tumor, but some tumor cells did not fluoresce.
authors.affiliation: Section of Neurosurgery, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03756, USA. Wesley.Whitson@Hitchcock.org
authors.forename: Wesley J
authors.initials: WJ
authors.lastname: Whitson
authors.forename: Pablo A
authors.initials: PA
authors.lastname: Valdes
authors.forename: Brent T
authors.initials: BT
authors.lastname: Harris
authors.forename: Keith D
authors.initials: KD
authors.lastname: Paulsen
authors.forename: David W
authors.initials: DW
authors.lastname: Roberts
mesh_terms: D000622:Aminolevulinic Acid; D003952:Diagnostic Imaging / Q000379:methods; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D008577:Meningeal Neoplasms / Q000473:pathology* / Q000601:surgery; D008579:Meningioma / Q000473:pathology* / Q000601:surgery; D018613:Microscopy, Confocal; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000601:surgery; D017319:Photosensitizing Agents; D025321:Surgery, Computer-Assisted
chemical_list: D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid